A comparative study of endothelial cells from different sources for use in small calibre vascular graft seeding.

The work in this thesis was carried out to examine currently acknowledged sources of endothelial cells for use in prosthetic graft seeding with the aim of assessing their practicality and applicability in a human clinical situation. Chapter 1 reviews the theories of the aetiology of peripheral vascular disease and discusses the clinical presentation and natural history of lower limb ischaemia. Chapter 2 reviews the therapeutic modalities currently available and Chapter 3 the current status of knowledge regarding why one such modality - bypass grafting - fails. Chapter 4 reviews our knowledge of endothelial cell function with emphasis on relevance to graft seeding and experience with seeding since its introduction in 1976. The experimental work is based on three cell types from four sources. In Chapter 5 the isolation of human umbilical vein endothelial cells is described, with assessment of cell yield and coagulation functions. Data on the antigenicity of such cells is presented using quantification of MHC Class II antigens and lymphoproliferative ability. Chapter 6 details the application of a similar isolation method to human saphenous vein segments. Chapter 7 details a new isolation method for obtaining microvascular endothelial cells from human omentum with assessment of cell yield, purity, function and ability to adhere to polytetrafluoroethylene. My experience with the application of the technique to human superficial fat is described in Chapter 8. Chapter 9 describes the modifications necessary to apply this technique to canine omentum and Chapter 10 recounts the results of a series of in vivo experiments in a canine model - assessing autologously seeded graft thrombogenicity and patency. In the last Chapter the results of my experiments are reviewed and an overall assessment of the potential of the various cell sources in a human clinical situation made. Possible avenues of research uncovered by my work are presented.